CARBON FIBER REINFORCED PLASTICS

SUBMITTED BY: SUMEET SHARMAE-Mail:sumeetsharma005@gmail.com

UNDER GUIDANCE OF: DR. D.R. PESHWEDEPARTMENT OF METALLURGICAL AND MATERIALS ENGINEERING

Visvesvaraya National Institute of Technology, Nagpur, Maharashtra

WHAT ARE CFRP?• Fibre-reinforced polymer(FRP), also Fibre-reinforced plastic, is

a composite material made of a polymer matrix reinforced with fibres.

FIBER

• FRP with carbon fibers are called CARBON FIBER REINFORCED PLASTICS OR CARBON FIBER REINFORCED POLYMERS(CFRP)

MATRIX

GLASSCARBON ARAMID ASBESTOS

WOOD

EPOXY POLYESTER THERMOSETTING

PLASTICS

PHENOL FORMLDEHYDE

Introduction to CFRP• Technical grade carbon fibres were developed in the

mid 1960s.• Composite’s properties are mainly influenced by the

choice of fibers.• Carbon fiber reinforced plastic (CFRP or CRP) is a light-

weight, high strength, composite material. • CFRP composites use thermosetting resins such as

epoxy, polyester, or vinyl ester.• When thermoplastic resins are used in CFRP

Composites, called "Carbon Fiber Reinforced Thermoplastic Composites(CFRTP).

MANUFACTURE OF CFRP• Fibre preforms are how the fibres are manufactured before being bonded to the matrix.

Textile processing techniques for PREFORMS

WEAVING

BRAIDING

KNITTINGSTITCHING

Carbon fibre preforms

sheets

Continous mats

Continous fibres for spray applications

Fibres in z-direction

• High strength, rigidity and pronounced anisotropy are achieved by a unidirectional (UD) arrangement of the fibres or the prepregs themselves.

• Prepregs made from woven fabrics are employed for components that have to be isotropic in one plane (orthotropic).In general, the fibre content of such elements will be about 50 percent by volume.

• Resin influence the essential properties of the resulting products, and also determines their processibility, manufacturing time and cost.

Pre-impregnated fibre(Prepregs)

High quality textile fabrics

Curabe resinEconomical

Fbre typeStrength

Modulus

Other properties

+

AUTOCLAVE MOLDING• Individual sheets of prepreg material are laid-up and placed in open mold. • Material is covered with release film, bleeder/breather material and

vacuum bag. • A vacuum is pulled on part and the entire mould is placed into an

autoclave (heated pressure vessel). The part is cured with a continuous vacuum to extract entrapped gasses from laminate.

• This process, however, make the fabrication costs expensive due to costly autoclave system and cold storage of prepreg .

MANUFACTURING OF CFRP…

VACUUM ASSISTED RESIN TRANSFER MOLDING•VaRTM is an alternative method to autoclave moulding available at a lower cost. •In VaRTM, dry carbon fibers or cloth are mounted on a mold and sealed by a flexible vacuum bag. •Resin is then drawn into the dry preform by a vacuum pump and cured under atmospheric pressure. •VaRTM has the potential to reduce fabrication costs, as it requires no expensive prepregs or autoclave systems .•Allows precise tolerances and detailed shaping but can sometimes fail to fully saturate the fabric leading to weak spots in the final shape.

MANUFACTURING OF CFRP…

NEW EMERGING TECHNIQUESSINGLE LINE INJECTION(SLI) TECHNIQUE:• Producing high-quality fibre composite components with the best possible

laminate and surface quality in a cost-optimised production process.Principle of the SLI Method• Approach is to combine the advantages of the raw material of the liquid resin

technology with the laminate quality of the Prepreg autoclave technology.• The advantage of this method over LRI method is that the resin is injected under

pressure and that the laminate can be compacted by the autoclave pressure.• Evacuation of the fibre preform as well as the injection of the resin system is

carried out with same resin transfer line.This resin transfer line can be arranged on the fibre preform in any arrangement to shorten the flow path and, with that, the injection time.

Fig:SLI technique

MANUFACTURING OF CFRP…

Variation of fibre volume content • An additional characteristic of the SLI method is the possibility to

directly influence the fibre content by means of the process parameters.

• If the autoclave pressure is adjusted same as the inner resin pressure, the fibre preform can relax in the thickness direction and can support the impregnation due to greater permeability.

• If the fibre preform is completely impregnated, the autoclave pressing on the fibre material can be increased by reducing the injection pressure until the desired fibre volume content of typically 60% is reached.

Fig :Pressure distribution during injection and adjustment phase in SLI

Properties of CFRP Composites• Light Weight -

An aluminum structure of equal strength, would likely weigh 1.5 times that of the carbon fiber structure.

• Stronger - Not only lighter, but CFRP composites are much stronger and stiffer per unit of weight.

For e.g. CFRP stiffness per unit weight= 2/3 of that of aluminum Stiffness and strength higher than Iron.

GFRP70% GLASS FIBRE BY WEIGHT

CFRP70%CARBON FIBRE BY WEIGHT

DENSITY=0.065 pounds per cu.inch

DENSITY=0.055 pounds per cu.inch

CFRPYoung’s modulus=245-640 KN/mm^2

Tensile strength=1900-3400 N/mm^2

Disadvantages of CFRP Composites• Cost - There is a reason why carbon fiber is not used in every single application.

CFRP composites are cost prohibitive in many instances.

Raw carbon fiber on a price per pound, can be 5-times to 25-times more expensive than fiberglass. This disparity is even greater when comparing steel to CFRP composites.

• Conductivity - This can be both an advantage to carbon fiber composites, or a disadvantage depending on the application. Carbon fiber is extremely conductive, while glass fiber is insulative. Thermal conductivity equivalent to copper. For example, in the utility industry, many products are required to use GFRP. It is also one of the reasons why ladders use glass fiber as the ladder rails. If a fiberglass ladder were to come in contact with a powerline, the chances of electrocution are much lower. This would not be the case with a CFRP ladder.

COST depends onCurrent market conditions

Type of carbon fibreFibre tow size

Demand and supply

aerospacecommercial

Use of different properties of CFRP for various apllications

Fig :comparison of properties of CFRP with some major materials

APPLICATION OF CFRP IN AIRCRAFTS• A large-scale structure such as an aircraft wing can be fabricated with

CFRP (integral molding) as a single component ,this may help sometimes to reduce weight by removing certain additional components sometimes.

Fig:Components of A380 made of CFRP

Expanded Use of CFRP in the Automotive Industry• If CFRP is used for 17% of an automobile's parts, its weight can be reduced by

about 30% of a standard automobile.

Reducing CO2 Emissions over the Product Life Cycle through Weight Reduction

• CFRP can greatly reduce fuel consumption by making automobiles and aircraft lighter. As a result, adoption of CFRP reduces CO2 emissions over the entire life cycle of the product, from the raw material and material manufacturing stages, right through to product use and disposal.

• About 35 tons of CFRP are used in the super-sized Airbus A380, which went into service in 2007. The Boeing 787, a mid-size model that is expected to go into service in 2010, will also use around 35 tons of CFRP per plane, accounting for about 50% of the structural elements. It is expected that aircraft weight will be reduced by about 20% as a result.

Fig: The Boeing 787, which uses CFRP for its structural parts

Fig: cross-section of turbine blade

Fig: light weight CNG cylinder used in trucks and buses

• By using CFRP for 50% of the weight of an aircraft, the resulting savings in CO2 emissions from improved fuel efficiency can average 27,000 tons per aircraft (7% reduction) over a ten-year product life cycle. This is equivalent to about 2,700 tons of CO2 per year. If CFRP were adopted for 15,000 passenger jets worldwide, the annual reduction of CO2 emissions would be about 40.5 million tons.

Fig: Overall Carbon di oxide emmisions for life of 10 years of conventional vehicle and aircraft

Carbon Composite (CFRP) Friction BearingsFriction bearings commonly use lubricating oil to separate the moving component from the mated non-moving bearing surface. Friction bearing surfaces commonly consist of a material that is softer than the supported component

CFRP friction bearings provide excellent dry running characteristics and can be used in operation after lubrication system failure making them an ideal solution for use in pumps and construction machinery as well as in mechanical engineering and shipbuilding or in offshore and onshore facilities to reduce maintenance and increase reliability. It can withstand up to 260 degree Celsius.

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